More particularly, the invention relates to a floor panel for forming a floor covering of the type wherein the floor panel comprises a layer-shaped substrate, as well as a decorative top layer located above the substrate; and wherein the substrate comprises at least a layer which is realized on the basis of a composition comprising at least a thermoplastic synthetic material.
The term “layer-shaped substrate” indicates that the substrate is composed of one or more layers, more particularly material layers.
It is also noted that the decorative top layer does not necessarily have to adjoin directly to the substrate.
Such type of floor panel is known, amongst others, from the documents WO 01/44669, WO 2011/085306, WO 2013/179260, WO 2013/179261, WO 2014/117887 and WO 2015/011049.
From the herein above-mentioned documents, various synthetic materials are known, on the basis of which the substrate of the floor panel may be made. However, many of these synthetic materials, such as polyvinyl chloride (PVC), are criticized.
In fact, they possibly form a problem seen from an environmental point of view. For example, for the production of PVC plasticizers have to be used, such as plasticizers from the group of phthalates. Such plasticizers, however, are critically assessed in recent juridical regulations.
WO 2014/111192 discloses a substrate for floor panels, which forms an alternative for substrates made on the basis of PVC. The substrate is made on the basis of a thermoplastic matrix material and a cross-linked polymer in powder form which is embedded in the matrix material. The thermoplastic matrix material concerns a polyolefin, such as polypropylene (PP) or polyethylene (PE), or an olefin copolymer, such as ethylene-propylene-diene monomer (EPDM) rubber.
A disadvantage of such substrates based on PP or PE is that, under the influence of, for example, sunlight or underfloor heating, they can deform to such an extent that cracks or gaps can occur between such coupled together floor panels. Moreover, the risk of such crack or gap formation is higher than with PVC-based substrates.
Another disadvantage is that with such substrates based on PP or PE, it is relatively difficult to produce a solid and at the same time mechanically strong floor panel in respect to, for example, PVC-based substrates.
Said WO '049 mentions, amongst others, polyethylene terephthalate, abbreviated PET, as a synthetic material which can be applied for manufacturing the substrate of the floor panel.
A disadvantage of such PET-based substrate is that the fatigue in the substrate under the influence of load can be considerable. This is primarily disadvantageous in the case that coupling parts, such as snap profiles, are manufactured from the material of the substrate. In fact, the fatigue may lead to damage or breaking of these coupling parts.
Another disadvantage is that such PET-based substrate may be rather brittle.
Another disadvantage is that with such PET-based substrate there is a relatively high risk of crack or gap formation between the coupled floor panels due to deformation under the influence of, for example, sunlight or underfloor heating.